Apparatus and method for communication network

ABSTRACT

A control apparatus (40) determines a control value to be supplied to a node (604) in a communication network so as to achieve a setpoint of Quality of Service (QoS) performance required by a traffic flow transferred through the communication network. This control value causes the node (604) to adjust allocation of network resources to the traffic flow. The control apparatus (40) corrects the control value to be supplied to the node (604) on the basis of a control delay between the control apparatus (40) and the node (604) and on the basis of a trend in changes in a traffic-related parameter. It is thus, for example, possible to contribute to stabilizing control for guaranteeing QoS performance required by a traffic flow even when there is a non-negligible control delay.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/JP2017/045068 filed Dec. 15, 2017, claiming priority based onJapanese Patent Application No. 2017-044323, filed Mar. 8, 2017 thedisclosures of which are incorporated herein in their entirety byreference.

TECHNICAL FIELD

The present disclosure relates to control over a communication networkand, in particular, to control of a node in a communication network forachieving a target value (setpoint) required by a traffic flowtransferred through the communication network.

BACKGROUND ART

Providing ultra-low latency services through a radio communicationnetwork has been studied. Ultra-low latency services may include missioncritical communications. For example, the 3rd Generation PartnershipProject (3GPP) has started to work on the standardization for the fifthgeneration mobile communication system (5G), i.e., 3GPP Release 14, in2016 to make it a commercial reality in 2020. The requirements for the5G system architecture include support of mission criticalcommunications.

Ultra-low latency services or mission critical communications include,for example, intelligent transport systems, industrial automation,robotics, the haptic or tactile internet, virtual reality, and augmentedreality. The ultra-low latency services and mission criticalcommunications require end-to-end latency in the order of milliseconds.For example, Non-patent Literature 1 describes that 1-millisecondend-to-end latency is required in tactile internet applications.

Ultra-low latency services and mission critical communications alsorequire reliability. The term “reliability” means a capability ofguaranteeing message transmission within a defined end-to-end latency(i.e., a delay budget, e.g., 1 millisecond).

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2014-197391 A-   Patent Literature 2: JP 2008-124748 A-   Patent Literature 3: WO 2016/157753 A1

Non Patent Literature

-   Non-patent Literature 1: ITU-T Technology Watch Report (August    2014)—The Tactile Internet, [retrieved on 2017 Feb. 27], <URL:    http://www.itu.int/oth/T2301000023/en>

SUMMARY OF INVENTION Technical Problem

The inventors have studied control over a communication network forachieving a target value (or setpoint) of Quality of Service (QoS)(e.g., end-to-end latency) required by a traffic flow transferredthrough the communication network. In some implementations, a controlapparatus performs feedback control as described below. The controlapparatus acquires a measured value of QoS performance related to atraffic flow transferred through a communications network and comparesthe measured value with a target value (or setpoint) of the QoSperformance. Then, the control apparatus determines a control value tobe supplied to a node in the communication network to achieve thesetpoint is achieved.

However, it should be noted that such feedback control is affected by achange in a traffic-related parameter regarding the traffic flow. Thetraffic-related parameter is a parameter that affects the determinationof the control value for achieving the setpoint.

As an example, consider control for guaranteeing end-to-end latencyrequired by a traffic flow transferred on a communication path betweentwo end nodes, such as a sensor and an actuator (hereinafter referred toas an end-to-end path). In this control, the setpoint of the feedbackcontrol may be, for example, end-to-end latency, end-to-end throughput,or an acceptable delay for the communication network. The control valuefor the feedback control may be guaranteed QoS for the traffic flow, forexample at least one of a priority, a guaranteed delay, and a guaranteedbit rate. The traffic-related parameter may be, for example, the size ofdata to be sent in one communication event that the end-to-end latencyis guaranteed. Additionally or alternatively, the traffic-relatedparameter may include at least one of a data rate per communicationevent and an interval between communications in a communication event.The traffic-related parameter may be another parameter that relates tothe pattern of the traffic flow and changes as the transmission datasize or the data rate between the end nodes changes.

As an example, when image data or video data is transmitted between theend nodes, the data size and data rate per communication event changesdepending on the change in the image resolution or the frame rate.Alternatively, when a set of feature vectors regarding feature points(local features) extracted from an image is transmitted between the endnodes, the data size and data rate per communication event changesdepending on the change in the number of feature points extracted fromthe image. It is desirable that the control apparatus is able to ensurethe defined end-to-end latency even when the traffic-related parameter(e.g., the data size per communication event) changes.

It should be also noted that such feedback control is affected by acontrol delay. As the control delay between the control apparatus andthe nodes increases, the feedback control becomes more difficult. Inparticular, when the control delay is longer than the interval at whichchanges in the traffic-related parameter occur, it is difficult tostabilize the control for guaranteeing the QoS performance required bythe traffic flow.

Incidentally, Patent Literature 1 discloses feedback control forcontrolling a process through a radio communication network. PatentLiterature 2 discloses control of a node through a network (e.g., anInternet Protocol (IP) network). Specifically, in Patent Literature 2, acontrol apparatus estimates a current process value while taking intoaccount a delay in the network, and generates a control output based onthe estimated process value. Patent Literature 3 discloses that aService Capability Exposure Function (SCEF) receives communicationpattern information from an application-layer entity and sends s networkparameter derived from the communication pattern information to anetwork entity. However, Patent Literature 1, Patent Literature2, orPatent Literature 3 does not explicitly disclose how to compensate forthe above-described change in the traffic-related parameter when thereis a control delay.

One of the objects to be attained by embodiments disclosed herein is toprovide an apparatus, a method, and a program that contribute tostabilizing control for guaranteeing QoS performance required by atraffic flow transferred through a communication network even when thereis a non-negligible control delay. It should be noted that theabove-described object is merely one of the objects to be attained bythe embodiments disclosed herein. Other objects or problems and novelfeatures will be made apparent from the following description and theaccompanying drawings.

Solution to Problem

In a first aspect, a control apparatus includes a memory, and at leastone processor coupled to the memory and configured to execute aplurality of modules. The modules include a control module, a monitoringmodule, an acquisition module, and a correction module. The controlmodule is configured to determine a control value to be supplied to anode in a communication network so as to achieve a target value (orsetpoint) of Quality of Service (QoS) performance required by a trafficflow transferred through the communication network. The control valuecauses the node to adjust allocation of network resources to the trafficflow. The monitoring module is configured to monitor a traffic-relatedparameter regarding the traffic flow. The acquisition module isconfigured to acquire a control delay between the control apparatus andthe node. The correction module is configured to correct the controlvalue based on the control delay and on a trend in changes in thetraffic-related parameter.

In a second aspect, a method performed by a control apparatus, includes:

(a) determining a control value to be supplied to a node in acommunication network so as to achieve a target value (or setpoint) ofQuality of Service (QoS) performance required by a traffic flowtransferred through the communication network, the control value causingthe node to adjust allocation of network resources to the traffic flow;(b) monitoring a traffic-related parameter regarding the traffic flow;(c) acquiring a control delay between the control apparatus and thenode; and(d) correcting the control value based on the control delay and on atrend in changes in the traffic-related parameter.

In a third aspect, a program includes a set of instructions (softwarecodes) that, when loaded into a computer, causes the computer to performa method according to the above-described second aspect.

Advantageous Effects of Invention

According to the above-described aspects, it is possible to provide anapparatus, a method, and a program that contribute to stabilizingcontrol for guaranteeing QoS performance required by a traffic flowtransferred through a communication network even when there is anon-negligible control delay.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a configuration example of a communication networkaccording to a first embodiment;

FIG. 2 shows an example of an end-to-end path;

FIG. 3 shows an example of an end-to-end path;

FIG. 4 shows an example of an end-to-end path;

FIG. 5 shows an example of an end-to-end path;

FIG. 6 is a block diagram showing an example of control performed by acontrol apparatus according to the first embodiment;

FIG. 7 is a flowchart showing an example of operations performed by acontrol apparatus according to the first embodiment; and

FIG. 8 is a block diagram showing a configuration example of a controlapparatus.

DESCRIPTION OF EMBODIMENTS

Specific embodiments will be described hereinafter in detail withreference to the drawings. The same or corresponding elements aredenoted by the same symbols throughout the drawings, and duplicatedexplanations are omitted as necessary for the sake of clarity.

First Embodiment

FIG. 1 shows a configuration example of a communication networkaccording to some embodiments including this embodiment. In the exampleshown in FIG. 1, the communication network includes an end node 10,intermediate nodes 20A and 20B, and an end node 30. An end-to-end path100 is a communication path from the end node 10 to the end node 30. Theend node 10 may be referred to as a sender end node while the end node30 may be referred to as a receiver end node.

In the cases of the tactile internet and industrial automation, the endnode 10 may be a computer installed in a sensor and the end node 30 maybe a computer installed in an actuator. In the case of an IntelligentTransportation System (ITS), both of the end nodes 10 and 30 may becomputers installed in automobiles. Alternatively, one of the end nodes10 and 30 may be a computer installed in an automobile while the otherend node may be an ITS application server.

The end-to-end path 100 is composed of two or more path segments 110.Accordingly, the end-to-end path 100 includes at least one intermediatenode 20. In the example shown in FIG. 1, the end-to-end path 100 isdivided into three path segments 110A, 110B and 110C. The path segment110A is a communication path from the (sender) end node 10 to theintermediate node 20A. The path segment 110B is a communication pathfrom the intermediate node 20A to the intermediate node 20B. The pathsegment 110C is a communication path from the intermediate node 20B tothe (receiver) end node 30.

The end-to-end path 100 is a communication path in the application layerand transfers application-layer messages. In other words, the end-to-endpath 100 transfers an application-layer traffic flow. Both of the endnodes 10 and 30 support an application-layer protocol and processapplication-layer messages. The traffic flow may also be referred to asa packet flow or a data flow.

Further, at least one intermediate node 20 may support theapplication-layer protocol and process application-layer messages. Thatis, a communication event (or a communication transaction) that isperformed on the end-to-end path 100 may include two or moreapplication-layer communications.

For example, in the above-described case of the haptic internet andindustrial automation, at least one intermediate node 20 may be acontrol/steering server that controls the actuator (i.e., the end node30) on the basis of sensing data received from the sensor (i.e., the endnode 10). In the case of the Intelligent Transportation System (ITS), atleast one intermediate node 20 may be an ITS server that receives amessage or data from an automobile (i.e., the end node 10) and controlsthe automobile or another automobile (i.e., the end node 30).

Additionally or alternatively, some or all of the one or moreintermediate nodes 20 may support the network layer (i.e., Layer 3,e.g., the Internet Protocol (IP) layer) and transfer a packet(s)containing an application-layer message between the end nodes 10 and 30.For example, each intermediate node 20 may be an IP router or a gateway.

Additionally or alternatively, at least one intermediate node 20 may bea RAN node (e.g., base station, eNodeB, or Radio Network Controller(RNC)) that communicates with the end node 10 or 30 through an airinterface.

FIGS. 2 to 5 show several specific examples of the end-to-end path 100.In the examples shown in FIGS. 2-5, the end-to-end path 100 includes aradio communication network (i.e., a Radio Access Network (RAN), or aRAN and a core network). In the example shown in FIG. 2, the end-to-endpath 100 is a communication path from a radio terminal (User Equipment(UE)) 210 to an application server 270. Accordingly, the UE 210corresponds to the (sender) end node 10 and the application server 270corresponds to the (receiver) end node 30.

The end-to-end path 100 shown in FIG. 2 is divided into two pathsegments 110A and 110B by a RAN node 230. The RAN node 230 correspondsto the intermediate node 20. The path segment 110A in FIG. 2 is acommunication path from the UE 210 to the RAN node 230 through a RAN 220(i.e., an uplink air interface). The path segment 110B in FIG. 2 is acommunication path from the RAN node 230 to the application server 270.The path segment 110B in FIG. 2 passes through a core network 240, acore network (CN) gateway 250, and a Packet Data Network (PDN) 260. Thecore network 240 is for example an Evolved Packet Core (EPC) or aUniversal Mobile Telecommunications System (UMTS) packet core, while theCN gateway 250 is for example a PDN Gateway (PGW) or a Gateway GPRSSupport Node (GGSN).

In the example shown in FIG. 3, the end-to-end path 100 is a round-trippath that starts from a UE 310, passes through an application server370, and returns to the UE 310. Accordingly, the UE 310 corresponds toboth the (sender) end node 10 and the (receiver) end node 30.

The end-to-end path 100 shown in FIG. 3 is divided into four pathsegments 110A, 110B, 110C and 110D by a RAN node 330 and an applicationserver 370. The path segment 110A in FIG. 3 is a communication path froma UE 310 to the RAN node 330 through a RAN 320 (i.e., an uplink airinterface). The path segment 110B in FIG. 3 is a communication path fromthe RAN node 330 to the application server 370. The path segment 110C inFIG. 3 is a communication path from the application server 370 to theRAN node 330. The path segments 110B and 110C in FIG. 3 pass through acore network 340, a CN gateway 350, and a PDN 360. The path segment 110Din FIG. 3 is a communication path from the RAN node 330 to the UE 310through the RAN 320 (i.e., a downlink air interface).

The example shown in FIG. 4 is a modified example of the example shownin FIG. 3. That is, in the example shown in FIG. 4, the end-to-end path100 starts from the UE 310, passes through the application server 370,and reaches a UE 490. Accordingly, the UE 310 corresponds to the(sender) end node 10 and the UE 490 corresponds to the (receiver) endnode 30. The path segment 110C in FIG. 4 is a communication path fromthe application server 370 to a RAN node 480. The path segment 110D inFIG. 4 is a communication path from the RAN node 480 to the UE 490through the RAN 320 (i.e., downlink air interface). The RAN node 480 maybe identical to the RAN node 330.

The examples shown in FIG. 5 relates to Mobile Edge Computing (MEC). TheMEC offers, to application developers and content providers,cloud-computing capabilities and an information technology (IT) serviceenvironment in the RAN in close proximity to mobile subscribers. Thisenvironment provides ultra-low latency and high bandwidth as well asdirect access to radio network information (subscriber's location, cellload etc.) that can be leveraged by applications and services. The MECis based on a virtualized platform, similar to Network FunctionVirtualization (NFV). While NFV focuses on network functions, MECenables applications to be run at the edge of the network.

A mobile edge cloud 540 provides an application server 550 withcomputing resources, storage capacity, and an interface with a RAN. Morespecifically, the mobile edge cloud 540 provides a hosting environmentfor applications by providing Infrastructure as a Service (IaaS)facilities or Platform as a Service (PaaS) facilities. That is, theapplication server 550 may be an application (hereinafter referred to asan MEC application) hosted on a server (hereinafter referred to as anMEC server) in the mobile edge cloud 540. The mobile edge cloud 540 (orthe MEC server) can also be referred to as an Internet of Things (IoT)service enabler.

The end-to-end path 100 shown in FIG. 5 is divided into four pathsegments 110A, 110B, 110C and 110D by a RAN node 530 and the applicationserver 550. The path segment 110A in FIG. 5 is a communication path froma UE 510 to the RAN node 530 through a RAN 520 (i.e., an uplink airinterface). The path segment 110B in FIG. 5 is a communication path fromthe RAN node 530 to the application server 550 arranged in the MECenvironment. The path segment 110C in FIG. 5 is a communication pathfrom the application server 55 to the RAN node 530. The path segments110B and 110C in FIG. 5 pass through the mobile edge cloud 540. The pathsegment 110D in FIG. 5 is a communication path from the RAN node 530 tothe UE 510 through the RAN 520 (i.e., a downlink air interface).

Referring back to FIG. 1, a controller 40 shown in FIG. 1 is a controlapparatus configured to control a node in a communication network inorder to achieve a target value (or setpoint) of QoS performancerequired by a traffic flow transferred through the communicationnetwork. In order to control each path segment 110, the controller 40communicates with at least one node included in the path segment 110 orcommunicates with an entity that manages the path segment 110. Forexample, the controller 40 may communicate with the RAN node 230 tocontrol the path segment 110A (i.e., a RAN segment) shown in FIG. 2. Thecontroller 40 may communicate with at least one of the RAN node 230, theCN gateway 250, and the application server 270, to control the pathsegment 110B (i.e., a wired network segment) shown in FIG. 2.Additionally or alternatively, the controller 40 may communicate with acontrol entity (e.g., a Service Capability Exposure Function (SCEF) or aPolicy and Charging Rules Function (PCRF)) in the core network 240 tocontrol the path segment 110B shown in FIG. 2. That is, althoughrespective connection relations between the controller 40 and the fournodes 10, 20A, 20B and 30 included in the end-to-end path 100 are shownin FIG. 1, the controller 40 may communicate only with some of thesefour nodes.

The controller 40 may be a single computer system or may be(distributed) computer systems. In some implementations, the controller40 may be arranged in a core network (e.g., the core network 240 or 340)or may be arranged in a PDN (e.g., the PDN 260 or 360). For example, thecontroller 40 may be arranged in a control node (e.g., an SCEF) withinthe core network. In some implementations, the controller 40 may bearranged in the mobile edge cloud 540 (e.g., an MEC server or an IoTservice enabler) shown in FIG. 5. In some implementations, thecontroller 40 may be arranged in one of the nodes included in theend-to-end path 100 (e.g., the end node 10, one of the intermediatenodes 20, or the end node 30).

The controller 40 determines a control value to be supplied to a node ina communication network (e.g., the end node 10, one of the intermediatenodes 20, or the end node 30), so as to achieve a target value (orsetpoint) of Quality of Service (QoS) performance required by a trafficflow transferred through the communication network.

The setpoint of the QoS performance may be, for example, end-to-endlatency between the sender end node 10 and the receiver end node 30 ofthe traffic flow, target throughput of the traffic flow, or anacceptable delay for the communication network.

The control value causes the node to adjust allocation of networkresources to the traffic flow. The control value may be, for example,guaranteed QoS for the traffic flow. More specifically, the controlvalue may be at least one of a priority, a guaranteed delay, and aguaranteed bit rate. The control value can also be referred to as anetwork control policy.

In some implementations, the controller 40 may perform feedback controlas described below. The controller 40 acquires a measured value of theQoS performance regarding the traffic flow transferred through thecommunication network and compares the measured value with the setpointof the QoS performance. Then, the controller 40 determines a controlvalue to be supplied to the node in the communication network in such amanner that the setpoint is achieved.

Further, the controller 40 monitors a traffic-related parameterregarding the traffic flow. The traffic-related parameter affects thedetermination of the control value for achieving the setpoint of the QoSperformance. The traffic-related parameter may be, for example, the sizeof data to be sent in one communication event that the end-to-endlatency is guaranteed. Additionally or alternatively, thetraffic-related parameter may include at least one of a data rate percommunication event and an interval between communications in onecommunication event. The traffic-related parameter may be anotherparameter that relates to the pattern of the traffic flow and changes asthe transmission data size or the data rate per communication eventchanges.

In some implementations, the controller 40 may acquire a configured ormeasured value of the traffic-related parameter from the end node 10 or30. Additionally or alternatively, the controller 40 may acquire ameasured value of the traffic-related parameter from at least oneintermediate node 20 that takes part in the transfer of the trafficflow. Additionally or alternatively, the controller 40 may acquire aconfigured or measured value of the traffic-related parameter fromanother control entity.

In addition, the controller 40 acquires a control delay between thecontroller 40 and the node. In some implementations, the control delaymay be a predetermined constant value. In this case, the controller 40may read and use a value of the control delay stored in a memory, or mayreceive a value of the control delay from another node. However, thecontrol delay may vary depending on one or both of the load on thecontroller 40 and the load on the node that operates in accordance withthe control value received from the controller 40. Further, the controldelay may vary depending on the variation in the transfer delay in anetwork between the controller 40 and the node. Further, the controldelay may vary depending on the number of terminals connected to thenode. Accordingly, in some implementations, the controller 40 maymeasure the control delay. For example, the controller 40 may transmitto the node a packet containing a time stamp indicative of the time oftransmission. The node may then acquire a time stamp upon receiving thispacket, and estimate a one-way delay time based on the differencebetween the two time stamps. The controller 40 may receive the estimatedone-way delay time from the node.

Further, the controller 40 corrects the control value to be supplied tothe node, on the basis of the control delay and on the basis of a trendin changes in the traffic-related parameter. Specifically, thecontroller 40 may correct the control value in such a manner that thecontrol value is consistent with an estimated value of thetraffic-related parameter at a point in time in the future when the nodeoperates in accordance with the control value. In other words, thecontroller 40 may treat the control delay and the change (or variation)in the flow-related parameter (e.g., the data size per communicationevent) as disturbances to the feedback control. The controller 40 mayperform feedforward control to compensate for the control delay and thechange in the flow-related parameter.

In some implementations, the controller 40 may estimate the trend inchanges in the traffic-related parameter from (a time series of)measured values of it and also estimate (or predict) a future value ofthe traffic-related parameter at a point in time in the future when thenode operates in accordance with the control value. Then, the controller40 may correct the control value in such a manner that the control valueis consistent with the estimated future value of the traffic-relatedparameter.

The following describes operations performed by the controller 40 inmore detail with reference to FIGS. 6 and 7. FIG. 6 is a block diagramshowing an example of the control for achieving the QoS setpointperformed by the controller 40. FIG. 7 is a flowchart showing a process700 that is an example of the operations performed by the controller 40.

In the example shown in FIG. 6, the controller 40 includes a controlunit 601, a first correction unit 602, and a second correction unit 603.The control unit 601 compares a measured value Y(t) of the QoSperformance with the setpoint SP thereof and thus generates a controlvalue C0(t) so as to achieve the setpoint SP. For example, in order toderive the control value C0(t) from the setpoint SP (e.g., theend-to-end latency), the initial value TRP_0 of the traffic-relatedparameter (e.g., the size of transmission data per communication event)may be taken into consideration. Step 701 in FIG. 7 corresponds to theprocessing performed in the control unit 601.

The first correction unit 602 receives a latest value TRP(t) of thetraffic-related parameter, corrects the control value C0(t) so as tocompensate for a temporal change in the traffic-related parameter, andthus generates a first corrected control value C1(t). The firstcorrection unit 602 may correct the control value C0(t) based on thedifference between the detected value TRP(t) of the traffic-relatedparameter and its initial value (i.e., reference value) TRP_0. Step 702in FIG. 7 corresponds to the processing performed in the firstcorrection unit 602.

The second correcting unit 603 further corrects the first correctedcontrol value C1(t) so as to compensate for a latest value CD(t) of thecontrol delay, and thus generates a second corrected control valueC2(t). As described above, the control delay may be a constant value.Step 703 in FIG. 7 corresponds to the processing performed in the secondcorrection unit 603.

A node 604 receives the second corrected control value C2(t) from thecontroller 40 and adjusts allocation of network resources to the trafficflow in accordance with the received control value. The control over theallocation of network resources may be, for example, scheduling of radioresources performed by a RAN node (e.g., eNB or RNC). For example, theRAN node may receive an acceptable delay as the control value andperform scheduling of radio resources to satisfy the acceptable delay.

The first correction unit 602 may receive the traffic-related parametera plurality of times. Further, the first and second correction units 602and 603 may generate the first and second corrected control values C1(t)and C2(t) based on the number of times of the reception. Each of thefirst and second correction units 602 and 603 may generate a controlvalue related to either of an input delay and an output delay.

For example, the RAN node includes a MAC scheduler that performs packetscheduling (i.e., Medium Access Control (MAC) scheduling). In someimplementations, the MAC scheduler uses a scheduling metric based on theEarliest Deadline First (EDF) approach (i.e., EDF metric). The EDFmetric is in proportion to the reciprocal of the difference between thedelay threshold and the head of line delay. The head of line delay meansa delay of the first packet of user's pending packets to be transmitted.The RAN node may receive an acceptable delay as the control value andchange the delay threshold used for the calculation of the EDF metricfor a packet flow related to the traffic flow or another packet flow insuch a manner that the received acceptable delay is achieved.

Additionally or alternatively, the control over the allocation ofnetwork resources may be control of communication bandwidth performed bya RAN node (e.g., eNB or RNC), a gateway (e.g., PGW or SGSN), or anotheruser-plane node that takes part in the transfer of the traffic flow.

The gateway (e.g., PGW or SGSN) and an IP router may control thetreatment (e.g., priority) of one or both of classification andscheduling for a packet flow related to the traffic flow or anotherpacket flow, so as to achieve the control value (e.g., the guaranteedbit rate). In some implementations, the gateway and the IP router maychange a class of the packet flow related to the traffic flow in orderto increase the priority of this packet flow. Additionally oralternatively, the gateway and the IP router may change a Weight FairQueuing (WFQ) weight applied to a queue that the packet flow related tothe traffic flow is to be stored in.

As understood from the above description, the controller 40 according tothis embodiment is configured to correct the control value to besupplied to the node based on the control delay and on a trend inchanges in the traffic-related parameter. The controller 40 according tothis embodiment thus can contribute to stabilizing the control forguaranteeing the QoS performance required by the traffic flowtransferred through the communication network even when there is anon-negligible control delay.

Second Embodiment

This embodiment provides a modified example of the control performed bythe controller 40 described in the first embodiment. Configurationexamples of a communication network according to this embodiment aresimilar to those shown in FIGS. 1 to 5.

The controller 40 according to this embodiment performs the secondcorrection based on the control delay (i.e., the correction performed bythe second correction unit 603 in Step 703 of FIG. 7) as follows. Thecontroller 40 monitors changes in the control delay and generates thesecond corrected control value C2(t) while taking into account thechanges in the control delay. As already described, the control delaymay vary depending on one or both of the load on the controller 40 andthe load on the node that operates in accordance with the control valuereceived from the controller 40. Further, the control delay may varydepending on the variation in the transfer delay in the network betweenthe controller 40 and the node. Further, the control delay may varydepending on the number of terminals connected to the node. Thecontroller 40 according to this embodiment compensates for the variationin the control delay. The controller 40 according to this embodimentthus can contribute to stabilizing the control for guaranteeing the QoSperformance required by the traffic flow transferred through thecommunication network even when there are variations in the controldelay.

Lastly, a configuration example of the controller 40 according to theabove embodiments will be described. FIG. 8 is a block diagram showing aconfiguration example of the controller 40. Referring to FIG. 8, thecontroller 40 includes a network interface 801, a processor 802, and amemory 803. The network interface 801 is used to communicate withnetwork entities (e.g., end nodes, intermediate nodes, a UE, a RAN node,a CN node, and an application server). The network interface 801 mayinclude, for example, a network interface card (NIC) conforming to theIEEE 802.3 series.

The processor 802 loads software (computer program(s)) from the memory803 and executes the loaded software, thereby performing processing ofthe controller 40 described in the above embodiments. The processor 802may be, for example, a microprocessor, an MPU, or a CPU. The processor802 may include a plurality of processors.

The memory 803 is composed of a volatile memory and a nonvolatilememory. The memory 803 may include a storage located apart from theprocessor 802. In this case, the processor 802 may access the memory 803through an I/O interface (not shown).

In the example shown in FIG. 8, the memory 803 is used to store softwaremodules including a control module 804, a monitoring module 805, anacquisition module 806, and a correction module 807. The processor 802loads the software modules from the memory 803 and executes the loadedsoftware modules, thereby performing the processing of the controller 40described by in the above embodiments.

The processor 802 can load and execute the control module 804, therebyperforming, for example, processing of the control unit 601 in FIG. 6(or processing in Step 701 in FIG. 7). The processor 802 can load andexecute the monitoring module 805, thereby monitoring a traffic-relatedparameter and detecting a change in the traffic-related parameter. Theprocessor 802 can load and execute the correction module 807, therebyperforming, for example, processing of the first and second correctionunits 602 and 603 in FIG. 6 (or processing in Steps 702 and 703 in FIG.7).

As described above with reference to FIG. 8, the processor included inthe controller 40 in the above embodiment may be configured to executeone or more programs including a set of instructions to cause a computerto perform an algorithm described above with reference to the drawings.These programs may be stored in various types of non-transitory computerreadable media and thereby supplied to computers. The non-transitorycomputer readable media includes various types of tangible storagemedia. Examples of the non-transitory computer readable media include amagnetic recording medium (such as a flexible disk, a magnetic tape, anda hard disk drive), a magneto-optic recording medium (such as amagneto-optic disk), a Compact Disc Read Only Memory (CD-ROM), CD-R,CD-R/W, and a semiconductor memory (such as a mask ROM, a ProgrammableROM (PROM), an Erasable PROM (EPROM), a flash ROM, and a Random AccessMemory (RAM)). These programs may be supplied to computers by usingvarious types of transitory computer readable media. Examples of thetransitory computer readable media include an electrical signal, anoptical signal, and an electromagnetic wave. The transitory computerreadable media can be used to supply programs to a computer through awired communication line (e.g., electric wires and optical fibers) or awireless communication line.

Other Embodiments

Each of the above embodiments may be used individually, or two or moreof the embodiments may be appropriately combined with one another.

Further, the above-described embodiments are merely examples ofapplications of the technical ideas obtained by the inventors. Thesetechnical ideas are not limited to the above-described embodiments andvarious modifications can be made thereto.

The whole or part of the embodiments disclosed above can be describedas, but not limited to, the following supplementary notes.

(Supplementary Note 1)

A control apparatus comprising:

a memory; and

at least one processor coupled to the memory and configured to execute aplurality of modules, wherein

the plurality of modules comprises:

a control module configured to determine a control value to be suppliedto a node in a communication network so as to achieve a setpoint ofQuality of Service (QoS) performance required by a traffic flowtransferred through the communication network, the control value causingthe node to adjust allocation of network resources to the traffic flow;

a monitoring module configured to monitor a traffic-related parameterregarding the traffic flow;

an acquisition module configured to acquire a control delay between thecontrol apparatus and the node; and

a correction module configured to correct the control value based on thecontrol delay and on a trend in changes in the traffic-relatedparameter.

(Supplementary Note 2)

The control apparatus described in Supplementary note 1, wherein thecorrection module is configured to correct the control value in such amanner that the control value is consistent with an estimated value ofthe traffic-related parameter at a point in time in the future when thenode operates in accordance with the control value.

(Supplementary Note 3)

The control apparatus described in Supplementary note 1 or 2, whereinthe correction module comprises:

a first correction module configured to generate a first correctedcontrol value by correcting the control value based on a latest value ofthe traffic-related parameter; and

a second correction module configured to generate a second correctedcontrol value by correcting the first corrected control value based onthe control delay.

(Supplementary Note 4)

The control apparatus described in Supplementary note 3, wherein thesecond corrected control value is consistent with an estimated value ofthe traffic-related parameter at a point in time in the future when thenode operates in accordance with the control value.

(Supplementary Note 5)

The control apparatus described in Supplementary note 3 or 4, wherein

-   -   the acquisition module is configured to monitor a change in the        control delay, and    -   the correction module is configured to generate the second        corrected control value while taking into account the change in        the control delay.        (Supplementary Note 6)

The control apparatus described in any one of Supplementary notes 1 to5, wherein the traffic-related parameter is a parameter that affects thedetermination of the control value for achieving the setpoint.

(Supplementary Note 7)

The control apparatus described in any one of Supplementary notes 1 to6, wherein the traffic-related parameter relates to at least one of adata size per communication event, a data rate of a communication event,and an interval between communications in the communication event.

(Supplementary Note 8)

The control apparatus described in any one of Supplementary notes 1 to7, wherein the setpoint is end-to-end latency between a sender end nodeand a receiver end node of the traffic flow, target throughput of thetraffic flow, or an acceptable delay for the communication network.

(Supplementary Note 9)

The control apparatus described in any one of Supplementary notes 1 to8, wherein the control value is guaranteed Quality of service (QoS) forthe traffic flow.

(Supplementary Note 10)

The control apparatus described in Supplementary note 9, wherein theguaranteed Quality of service (QoS) includes at least one of a priority,a guaranteed delay, and a guaranteed bit rate.

(Supplementary Note 11)

The control apparatus described in any one of Supplementary notes 1 to10, wherein the node includes at least one of a radio access networknode in the communication network and a core network node in thecommunication network.

(Supplementary Note 12)

A method performed by a control apparatus, the method comprising:

determining a control value to be supplied to a node in a communicationnetwork so as to achieve a setpoint of Quality of Service (QoS)performance required by a traffic flow transferred through thecommunication network, the control value causing the node to adjustallocation of network resources to the traffic flow;

monitoring a traffic-related parameter regarding the traffic flow;

acquiring a control delay between the control apparatus and the node;and

correcting the control value based on the control delay and on a trendin changes in the traffic-related parameter.

(Supplementary Note 13)

The method described in Supplementary note 12, wherein the correctingcomprises correcting the control value in such a manner that the controlvalue is consistent with an estimated value of the traffic-relatedparameter at a point in time in the future when the node operates inaccordance with the control value.

(Supplementary Note 14)

The method described in Supplementary note 12 or 13, wherein thecorrecting comprises:

generating a first corrected control value by correcting the controlvalue based on a latest value of the traffic-related parameter; and

generating a second corrected control value by correcting the firstcorrected control value based on the control delay.

(Supplementary Note 15)

The method described in Supplementary note 14, wherein the secondcorrected control value is consistent with an estimated value of thetraffic-related parameter at a point in time in the future when the nodeoperates in accordance with the control value.

(Supplementary Note 16)

The method described in Supplementary note 14 or 15, wherein

the acquiring comprises monitoring a change in the control delay, and

the generating the second corrected control value comprises determiningthe second corrected control value while taking into account the changein the control delay.

(Supplementary Note 17)

The method described in any one of Supplementary notes 12 to 16, whereinthe traffic-related parameter is a parameter that affects thedetermination of the control value for achieving the setpoint.

(Supplementary Note 18)

The method described in any one of Supplementary notes 12 to 17, whereinthe traffic-related parameter relates to at least one of a data size percommunication event, a data rate of a communication event, and aninterval between communications in the communication event.

(Supplementary Note 19)

The method described in any one of Supplementary notes 12 to 18, whereinthe setpoint is end-to-end latency between a sender end node and areceiver end node of the traffic flow, target throughput of the trafficflow, or an acceptable delay for the communication network.

(Supplementary Note 20)

The method described in any one of Supplementary notes 12 to 19, whereinthe control value is guaranteed Quality of service (QoS) for the trafficflow.

(Supplementary Note 21)

The method described in Supplementary note 20, wherein the guaranteedQuality of service (QoS) includes at least one of a priority, aguaranteed delay, and a guaranteed bit rate.

(Supplementary Note 22)

The method described in any one of Supplementary notes 12 to 21, whereinthe node includes at least one of a radio access network node in thecommunication network and a core network node in the communicationnetwork.

(Supplementary Note 23)

A program for causing a computer to perform a method performed by acontrol apparatus, the method comprising:

determining a control value to be supplied to a node in a communicationnetwork so as to achieve a setpoint of Quality of Service (QoS)performance required by a traffic flow transferred through thecommunication network, the control value causing the node to adjustallocation of network resources to the traffic flow;

monitoring a traffic-related parameter regarding the traffic flow;

acquiring a control delay between the control apparatus and the node;and

correcting the control value based on the control delay and on a trendin changes in the traffic-related parameter.

REFERENCE SIGNS LIST

-   10 END NODE-   20 INTERMEDIATE NODE-   30 END NODE-   40 CONTROLLER-   802 PROCESSOR-   803 MEMORY-   804 CONTROL MODULE-   805 MONITORING MODULE-   806 ACQUISITION MODULE-   807 CORRECTION MODULE

The invention claimed is:
 1. A control apparatus comprising: a memory;and at least one processor coupled to the memory and configured toexecute a plurality of modules, wherein the plurality of modulescomprises: a control module configured to determine a control value tobe supplied to a node in a communication network so as to achieve asetpoint of Quality of Service (QoS) performance required by a trafficflow transferred through the communication network, the control valuecausing the node to adjust allocation of network resources to thetraffic flow, wherein the QoS performance is end-to-end latency betweena sender end node and a receiver end node of the traffic flow, targetthroughput of the traffic flow, or an acceptable delay for thecommunication network, and wherein the setpoint is a target value of theend-to-end latency, target throughput, or acceptable delay; a monitoringmodule configured to monitor a traffic-related parameter regarding thetraffic flow, wherein the traffic-related parameter is a size of data tobe sent per communication event or a parameter that changes as the sizeof data to be sent per communication event changes; an acquisitionmodule configured to acquire a control delay between the controlapparatus and the node; and a correction module configured to correctthe control value based on the control delay and on a trend in changesin the traffic-related parameter.
 2. The control apparatus according toclaim 1, wherein the correction module is configured to correct thecontrol value in such a manner that the control value is consistent withan estimated value of the traffic-related parameter at a point in timein the future when the node operates in accordance with the controlvalue.
 3. The control apparatus according to claim 1, wherein thecorrection module comprises: a first correction module configured togenerate a first corrected control value by correcting the control valuebased on a latest value of the traffic-related parameter; and a secondcorrection module configured to generate a second corrected controlvalue by correcting the first corrected control value based on thecontrol delay.
 4. The control apparatus according to claim 3, whereinthe second corrected control value is consistent with an estimated valueof the traffic-related parameter at a point in time in the future whenthe node operates in accordance with the control value.
 5. The controlapparatus according to claim 3, wherein the acquisition module isconfigured to monitor a change in the control delay, and the correctionmodule is configured to generate the second corrected control valuewhile taking into account the change in the control delay.
 6. Thecontrol apparatus according to claim 1, wherein the control value isguaranteed Quality of service (QoS) for the traffic flow.
 7. The controlapparatus according to claim 6, wherein the guaranteed Quality ofservice (QoS) includes at least one of a priority, a guaranteed delay,and a guaranteed bit rate.
 8. The control apparatus according to claim1, wherein the node includes at least one of a radio access network nodein the communication network and a core network node in thecommunication network.
 9. A method performed by a control apparatus,comprising: determining a control value to be supplied to a node in acommunication network so as to achieve a setpoint of Quality of Service(QoS) performance required by a traffic flow transferred through thecommunication network, the control value causing the node to adjustallocation of network resources to the traffic flow, wherein the QoSperformance is end-to-end latency between a sender end node and areceiver end node of the traffic flow, target throughput of the trafficflow, or an acceptable delay for the communication network, and whereinthe setpoint is a target value of the end-to-end latency, targetthroughput, or acceptable delay; monitoring a traffic-related parameterregarding the traffic flow, wherein the traffic-related parameter is asize of data to be sent per communication event or a parameter thatchanges as the size of data to be sent per communication event changes;acquiring a control delay between the control apparatus and the node;and correcting the control value based on the control delay and on atrend in changes in the traffic-related parameter.
 10. The methodaccording to claim 9, wherein the correcting comprises correcting thecontrol value in such a manner that the control value is consistent withan estimated value of the traffic-related parameter at a point in timein the future when the node operates in accordance with the controlvalue.
 11. The method according to claim 9, wherein the correctingcomprises: generating a first corrected control value by correcting thecontrol value based on a latest value of the traffic-related parameter;and generating a second corrected control value by correcting the firstcorrected control value based on the control delay.
 12. The methodaccording to claim 11, wherein the second corrected control value isconsistent with an estimated value of the traffic-related parameter at apoint in time in the future when the node operates in accordance withthe control value.
 13. The method according to claim 11, wherein theacquiring comprises monitoring a change in the control delay, and thegenerating the second corrected control value comprises generating thesecond corrected control value while taking into account the change inthe control delay.
 14. The method according to claim 9, wherein thetraffic-related parameter is a parameter that affects the determinationof the control value for achieving the setpoint.
 15. A non-transitorycomputer readable medium storing a program for causing a computer toperform a method performed by a control apparatus, the methodcomprising: determining a control value to be supplied to a node in acommunication network so as to achieve a setpoint of Quality of Service(QoS) performance required by a traffic flow transferred through thecommunication network, the control value causing the node to adjustallocation of network resources to the traffic flow, wherein the QoSperformance is end-to-end latency between a sender end node and areceiver end node of the traffic flow, target throughput of the trafficflow, or an acceptable delay for the communication network, and whereinthe setpoint is a target value of the end-to-end latency, targetthroughput, or acceptable delay; monitoring a traffic-related parameterregarding the traffic flow, wherein the traffic-related parameter is asize of data to be sent per communication event or a parameter thatchanges as the size of data to be sent per communication event changes;acquiring a control delay between the control apparatus and the node;and correcting the control value based on the control delay and on atrend in changes in the traffic-related parameter.